The Question:

What's the world's smallest flower?

The Answer:

The smallest known flowering plants are in the genus
Wolffia, which float
on the surface of quiet streams and ponds. The entire plant—flower and
all—is less than a millimeter long. A bouquet of a dozen could fit on
the head of a pin.

For more on this, and other interesting facts about the plant
world, see our Plant Hall of
Fame.